Installed Transfer Switch in House

[BLoflin]

This question (about not connecting PowerBoost ground to home wiring) come us a lot.

First let me state, I'm not a lawyer, or a doctor or work for UL.... so any actions you take based on my "opinions" I am not responsible for.

Most of the safety codes for home wiring are for SAFETY, not for function. As a metaphor, you do NOT need to wear seat belts to drive (functionally, of course they are required legally in the US). Seat belts do not make driving better or easier, etc. They are there in case of a "problem" that is not the normal use (i.e. accident/rapid deceleration).

Not connecting the GND wire from PB to house, will not affect the normal use scenario (and obviously it allows (by defeating the GFCIs) normal usage.

(BTW, GFCI are also a SAFETY device not needed for normal use scenario, it is to protect against a problem/fault).

So without the GND in the PB (which is tied to the truck frame), if there was a fault scenario (with something in the truck or connected to the truck A/C outlets, a scenario like a frayed connection or one with moisture intrusion, or carbonized connections... that cause some amount of current to be carried by the GND in the PB), you have basically taken the safety measures out as the GFCIs in the truck won't sense (until the current is flowing thru you, if you are touching the truck and are grounded (i.e. standing on wet ground or holding on to a metal fence post or a natural gas line, etc). You are then counting on the breakers (and possibly the GFCIs) in the home to trip, which may be enough delay before that happens, to be most unpleasant for you (if not deadly).

There are probably other scenarios as well.

P.S. as way of an anecdotal story (but one that I actually knew the family, this is NOT an "internet story), a very sad story. Family was out doing outside chores around the home on a nice day. Washing the cars. Doing yard work. Some of the yard work tools were A/C (in this case the leaf blower). For convinence due to the length of the extension cord and the location where the husband was working, he ran the extension cord thru the front door and plugged into an inside wall circuit (i.e NOT GFCI'd). The wife was picking up as they were about done. A small portable tool chest was in the driveway as they were using tools out of it. She went to close it and bring it back in. Didn't see the extension cord was draped over the back edge. As she closed it (standing on the wet driveway from the car washing) the back of the metal toolkit lid pinched the extension cord and shorted it. She was electrocuted (yes died). Husband was of course racked with guilt. He just didn't understand there was a difference between inside outlets and outside outlets as far as Code Required safety measures (i.e. GFCIs). Just a very freak accident and scenario that ended very sadly.

TLDR: disconnecting GND in cord from PB to house circuit will not affect normal function, but you have eliminated some SAFETY measures, that under some problem/failure/fault scenarios could cause serious harm.

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[Meterman]

Thanks for all the replies and education. If only Ford knew what kind of forum conversation they would start by making the 7.2K W a bonded neutral LOL.

I have learned a lot and am still trying to understand if the risk of powering my home for an hour or two would really be as big of a risk as pointed out here.

Just curious, since I said I disconnected the ground in a double gang box, would connecting the ground from the 240V outlet to a earth ground help. I understand there's not a GFCI to trip, but would it address the random voltage that was suggested could take place on the wiring.

Just a thought.

 

[Meterman]

One other question, I have an enclosed trailer that I take my car to the track in. It was the real purpose of the generator. I was going to put a 240V receptible in it too so I have 120v outlets in the trailer and install an A/C unit. I also bought a 110V AC to 12V DC Converter Power Supply Adapter Switch Transformer Max 50A 600W so I can run my winch off the truck generator and remove the 12 volt battery that currently powers the winch.

Any potential issues here with the bonded neutral ground?

 

[kizzle_wizzle]

Regarding strange voltages without a ground present, I'm not seeing how that would happen with these trucks unless something else is off with the building its being connected to. These trucks are designed to power devices plugged into them, which have no ground rod present, so this shouldn't be necessary to provide clean voltage output. From what have read, the inverter actually outputs a much cleaner and more precisely monitored sine wave than a standard portable generator.

Often devices plugged into the truck will use the ground pin in their cord, but that is to protect for the case where a hot wire may be shorted to the the device itself, the cord is pinched causing a short, etc. In this case, the cable ran between the house and the truck still has a ground in it, so if its pinched or cut, the breaker in the truck will trip.

There are two things I'm still not sure about though:
1) Will GFCI outlets still function as designed in this configuration? I'm thinking they should should since they should still sense current returning to the receptacle on the ground wire.
2) Will a short to ground still trip the breaker in the house? Again, I believe they still will trip. Even if the current on the ground wire isn't destined for the ground, it will flow back to panel on the ground wire and then to the neutral on the truck via the ground/neutral bond in the houses panel, which should still trip the circuit breaker in the panel from an over current condition. If not, it should trip the breaker in the truck.

 

[Gros Ventre]

Keep in mind that the Bonded Neutral-Ground is an OSHA requirement for Generators used by a contractor on a jobsite. It is not a part of the NEC.

 

[Hullguy]

My advice is you are never wrong getting the right equipment to do a job correctly and safely. You see people injured and killed every day that take shortcuts. Be safe my friends

 

[Gros Ventre]

Correct: Either a Neutral switching sub-panel inside the house or a floating neutral set-up in your Powerboost. In both cases you need: 1-a 4 wire cable rated for your generator amperage; 2-that cable must not have two male plug ends; 3-Inlight of #2 an input box on your house (ie it is a male plug in the box); 4-an interlock between the generator input and the utility line input. The discussion of "why not just cut the ground wire between your truck and house" effectively leaves the truck frame at a potential (voltage) of the neutral wire. This can be bad when something shorts thru on your truck. Recognize the floating neutral places the truck frame at the ground of the house, so when something shorts the truck will behave just like the same short inside the house.

 

[OddManOut]

I have the Powerboost with 2.4kw standard 110/120 plugs, and I've got a little regret in not shelling out for the 7.2kw upgrade. Obviously, I can't pull 220/240v from the 110/120 plugs. No argument there. But...I do have 2400 watts from the truck, and I have a couple of small circuits I'd like to keep on during an outage (mainly the fridge). So I wonder....

A 240 wire has two hot wires (black), shared neutral (white) and shared ground. I could make a cord that has a 120v male end, which will connect the white wire, ground wire and only one black wire to plug into the Powerboost 2.4 kw outlet. The other end of the wire would have the normal female 240 end (with one unused black wire) that would plug into the Power Inlet Box.

Question: Would that allow me to get a Generac 6852 (8 circuit box) but use only 4 of those circuits (because I'm only energizing one bar)???

If that would work safely, then I could use my Powerboost as a small generator to easily keep just a couple of circuits powered during a power outage (one fridge, and maybe some lights). Obviously, I couldn't power anything that requires 240v (because I'm only supplying 120v to the Generac).

Thanks for taking time to read and respond.

 

[Gros Ventre]

240 VAC wiring uses 1-black, 1- red, 1-white, 1-bare. what you propose is doable... but I don't like it. Remember that in a breaker box the circuit positions are interleaved. In other words if you're going to do what you talk of then the circuits you power will alternate sides as you go down.

 

[Meterman]

One other question, I have an enclosed trailer that I take my car to the track in. It was the real purpose of the generator. I was going to put a 240V receptible in it too so I have 120v outlets in the trailer and install an A/C unit. I also bought a 110V AC to 12V DC Converter Power Supply Adapter Switch Transformer Max 50A 600W so I can run my winch off the truck generator and remove the 12 volt battery that currently powers the winch.

Any potential issues here with the bonded neutral ground?

Any thoughts on this?

 

[Gros Ventre]

So long as there isn't a link between the trailer ground and the trailer neutral, I thik it will work just fine. Effectively the trailer will be just like a jobsite...

 

[Ajzride]

Back to the house…

Could you add a disconnect to the house side so that the neutral ground bond could be removed while using pro-power and let the bond in the truck take over? Not sure how this would relate to the codes.

 

[jesaf00]

ITS ALIVE! I used the Generac 6852 from this thread, and a reliance 30a power input box. The generac doesn't come with the plug. I had to order it from the web and inside the box were about 5 pieces of paper that said "If product is faulty, do not return to the store." So you'll be forced to work with generac if it comes broken. You may be able to purchase from a local generac dealer, I didn't try.
Anyway, the generac works great. I have most of my house hooked up to the 10 circuits with the exception of heat and AC. Going to get a small portable AC unit for a sleeping room, or look into the multi split AC thing. Our unit is 20a constant, so even with a soft starter it just wasn't worth taking most of the power.
The only time the truck threw a ground fault was when we used the manual switch on the box to go from generator to utility power and the generator was still connected. It threw the ground fault when the generac box cut it off, as intended.

If you are in Jax / St Aug etc, call these guys. The number on their google listing is their house phone, this is their cell. Jack's Electrical Services - 904 626 8230

An electrician installed the Generac 6852 today and with no breakers turned on I get a ground fault detected right away when switching to truck power. Any ideas!?

 

[jesaf00]

An electrician installed the Generac 6852 today and with no breakers turned on I get a ground fault detected right away when switching to truck power. Any ideas!?

Looks like this MAY be related to a common install mistake with the 6852 where an electrician runs all the neutral lines from the 6852 to the bus bar on the sub panel. Those neutrals need to be tied to the neutrals going to your outlets/lights/devices in order to fully separate from the main power. Electrician is coming back tomorrow to rework.

 

[MDH]

Looks like this MAY be related to a common install mistake with the 6852 where an electrician runs all the neutral lines from the 6852 to the bus bar on the sub panel. Those neutrals need to be tied to the neutrals going to your outlets/lights/devices in order to fully separate from the main power. Electrician is coming back tomorrow to rework.

Can you post pictures of the install once the neutral lines are sorted out? Thanks in advance.

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